Method and apparatus for the production of process gas that includes water vapor and hydrogen formed by burning oxygen in a hydrogen-rich environment

ABSTRACT

The aim of the invention is the simple and economical production of a hydrogen-rich process gas from water vapour and hydrogen, whereby the proportion of water vapour to hydrogen may be precisely controllable and reproducible. Said aim is achieved, with a method and device for the production of a process gas for the treatment of substrates, in particular semiconductor substrates, in which the oxygen for formation of a process gas, comprising water vapour and hydrogen, is burnt in a hydrogen-rich environment in a combustion chamber.

BACKGROUND OF THE INVENTION

The present invention relates to a method and an apparatus for theproduction of a process gas for the treatment of substrates, especiallysemiconductor substrates.

Computer chips, as well as other electronic components, are manufacturedon semiconductor disks, so-called wafers. For this purpose, manyoperating steps and processes are necessary, such as, for example,structuring, lithography, ion implantation, etching or coating. Coatingprocesses are frequently carried out during a thermal treatment of thewafers in a prescribed process gas atmosphere. In this connection, it isknown to use a process gas comprising water vapor and oxygen for anoxygen-rich wet oxidation of the wafers. The oxygen-rich process gas isparticularly suitable for building up thick oxide layers of 2000angstroms at low thermal budget, as well as for the production of thingate-oxides having a layer thickness of less than approximately 40angstroms. Furthermore, a hydrogen-rich wet oxidation is known accordingto which the process gas comprises water vapor and hydrogen. Thehydrogen-rich process gas is particularly suitable for the selectiveoxidation of gate-stacks with metal gates or metal gate contacts.

For the production of the oxygen-rich process gas and of thehydrogen-rich process gas (i.e. a process gas comprising water vapor andoxygen or hydrogen), different methods were used in the past.

The oxygen-rich process gas was, for example, produced in a burnerhaving a combustion chamber in which oxygen and hydrogen were burned toproduce water vapor. For the combustion, more oxygen was always madeavailable than could be burned with the hydrogen. In this way, thereresulted an excess of oxygen, so that a process gas comprising watervapor and oxygen was formed. This process gas was subsequently conveyedvia an appropriate conduit into a process chamber for the treatment of asemiconductor wafer. Additional oxygen could be introduced into theconduit in order to establish the oxygen content in the process gas.

For the production of a hydrogen-rich process gas, in the past hydrogengas was mixed with water vapor, whereby the water vapor was produced bythe evaporation of distilled water. However, this method does not permithigh gas flows. Furthermore, the ratio of water vapor and hydrogencannot be precisely controlled and reproduced. A further drawback ofthis method is that contaminations frequently occur.

Proceeding from the known state of the art, it is therefore an object ofthe present invention to provide a method and an apparatus which, in astraightforward and economical manner, enable the production of ahydrogen-rich process gas comprising water vapor and hydrogen, wherebythe mixture ratio of water vapor and hydrogen can be preciselycontrolled and reproduced.

SUMMARY OF THE INVENTION

Pursuant to the invention, this object is realized with a method for theproduction of a process gas for the treatment of substrates, especiallysemiconductor substrates, in that oxygen for the formation of a processgas comprising water vapor and hydrogen is burned in a hydrogen-richenvironment in a combustion chamber. With this method, high gas flowsfrom the process gas can be achieved. Furthermore, the ratio betweenwater vapor and hydrogen can be precisely controlled and reproduced,since the quantity of the resulting water vapor is directly proportionalto the oxygen that is introduced and burned with the hydrogen.Furthermore, pure hydrogen results during the combustion, so that theprocess gas has a high purity.

Instead of oxygen, in general, an oxygen-containing gas, such as, forexample, NO or O₃, can be used, and similarly in place of hydrogen a gascontaining hydrogen or a hydrogen isotope, such as, for example, NH₃,deuterium, or NO₃, can be used.

To ensure that all of the oxygen in the combustion chamber is burned,the presence of unburned oxygen is detected downstream of the combustionchamber. If unburned oxygen is detected downstream of the combustionchamber, pursuant to one embodiment of the invention the method isinterrupted, since the unburned oxygen can form an oxyhydrogen gas or anexplosive gas mixture with the hydrogen that is present in the processgas. For this reason, preferably an inert gas is also introduced intothe process gas if unburned oxygen is detected downstream of thecombustion chamber in order to prevent the danger of the formation ofoxyhydrogen or explosive gas downstream of the combustion chamber.

Pursuant to one preferred embodiment of the invention, hydrogen isintroduced into the process gas downstream of the combustion chamber, asa result of which the hydrogen concentration in the process gas can beestablished as desired. The ratio of hydrogen to water vapor ispreferably set between the stoichiometric combustion (0% H₂) and 1000/1(0.1% H₂O).

The combustion chamber is advantageously filled with pure hydrogen priorto the combustion of oxygen, and oxygen is first introduced fortriggering the combustion, in order to prevent oxyhydrogen or explosivegas from forming in the combustion chamber which after the triggering ofthe combustion is not completely burned and exits the combustionchamber. Prior to the filling with hydrogen, the combustion chamberand/or the downstream gas system is advantageously flushed with inertgas (for example N₂, He or Ar) in order to remove possible atmosphericoxygen.

For the production of an oxygen-rich process gas in the same unit, theratio of oxygen to hydrogen in the combustion chamber is preferablychanged during the combustion. In this way, in a straightforward andeconomical manner, it is possible to change from a hydrogen-rich processgas to an oxygen-rich process gas to the extent that this is desired fora subsequent process. Furthermore, in this way, using the sameapparatus, different processes can be enhanced in subsequent apparatus,for example separate rapid heating units or in general units for thethermal treatment of substrates (semiconductors). To ensure that duringthe change between the production a hydrogen-rich and an oxygen-richprocess gas no oxyhydrogen or explosive gases are produced, astoichiometric combustion of oxygen and hydrogen is carried out for apredetermined period of time. Due to the stoichiometric combustion, theprevious excess hydrogen is displaced from the chamber by the resultingwater vapor. Only after all of the hydrogen is displaced, is the oxygencontent again increased in order to provide an oxygen-rich combustion.In this way, it is ensured that no oxyhydrogen or explosive gases areformed in the combustion chamber and/or in downstream gas systems, suchas, for example, the process chamber of rapid heating units. In thisconnection, for safety reasons the concentration of unburned oxygenand/or hydrogen can be monitored, thereby ensuring that a possibleoxygen/hydrogen mixture is below the explosion limit, which is afunction of pressure, temperature and further parameters (such as, forexample, UV irradiation).

For a precise setting of the oxygen concentration in the oxygen-richprocess gas, additional oxygen is preferably introduced downstream ofthe combustion chamber. The ratio of oxygen to hydrogen is preferablybetween 0% (complete combustion or 100% H₂O) and 100% (0.1% H₂O).

To prevent a production of oxyhydrogen or explosive gas in the conduitthat is disposed downstream of the combustion chamber, an oxygen supplyline is blocked downstream of the combustion chamber if a hydrogen-richprocess gas is produced in the combustion chamber. In the same manner, ahydrogen supply line is preferably blocked downstream of the combustionchamber if an oxygen-rich process gas is produced in the combustionchamber. Furthermore, the hydrogen supply line and the oxygen supplyline are engaged in opposition to one another, i.e. always only one ofthe two supply lines is open. For a changing of the process gas, afurther fluid is preferably introduced into the process gas downstreamof the combustion chamber in order to be able to enhance differentmechanisms during the subsequent substrate treatment. The further fluidcan be a gas that is reactive or inert for the subsequent thermalprocess for processing semiconductor wafers, or can be a mixture of suchgases (e.g. Ar, N₂).

Pursuant to one embodiment of the invention, an oxygen-rich process gasis first produced in the combustion chamber in that oxygen is burned ina hydrogen-poor environment, and subsequently the ratio of hydrogen tooxygen in the combustion chamber is changed for the combustion of oxygenin a hydrogen-rich environment. Thus, it is possible to selectivelystart with the production of a hydrogen-rich or oxygen-rich process gas,and subsequently it is possible to change as desired between theproduction of these two process gases without having to shut the burnerdown.

If an oxygen-rich combustion is effected in the combustion chamber, themethod is preferably interrupted and/or an inert gas is introduced intothe process gas if downstream of the combustion chamber unburnedhydrogen is detected by a device for detecting hydrogen (e.g. a hydrogensensor). In this way, the formation of an oxyhydrogen gas explosive gasmixture downstream of the combustion chamber is prevented.

When changing from a combustion of oxygen in a hydrogen-poor environmentto a hydrogen-rich environment, for a predetermined period of time astochiometric combustion of oxygen and hydrogen is preferably carriedout in order to ensure that the combustion chamber contains only watervapor and no unburned oxygen or hydrogen.

To prevent the formation of oxyhydrogen or explosive gases, thecombustion chamber is preferably rinsed with an inert gas prior to thecombustion process.

Pursuant to one embodiment of the invention, the process gas ispreferably used for the thermal treatment of at least one semiconductorwafer or semiconductor material, and within a treatment cycle is changedbetween a hydrogen-rich and an oxygen-rich process gas. The termtreatment cycle is intended to mean that the semiconductor (e.g.semiconductor wafer) is subjected to a temperature-time cycle thatincludes at least a heating-up and a cooling-off of the semiconductor.The semiconductor, which is generally in substrate form, can include Siand can be a III–V, II–VI, or IV—IV semiconductor.

Pursuant to an alternative embodiment, the process gas is used for thethermal treatment of at least one semiconductor wafer, and duringsuccessive thermal treatment cycles a change is made between ahydrogen-rich and an oxygen-rich process gas. During a thermal treatmentcycle, the concentration of hydrogen or oxygen in the water vapor of theprocess gas is preferably changed.

The object of the invention is also realized by an apparatus for theproduction of a process gas for the treatment of substrates, especiallysemiconductor substrates, which apparatus has a burner with a combustionchamber, at least one oxygen supply line and at least one hydrogensupply line into the combustion chamber, an ignition unit for ignitingan oxygen/hydrogen mixture in the combustion chamber, and a controlunit, which is controllable is such a way that for the formation of aprocess gas comprising water vapor and hydrogen, the oxygen is ignitedin a hydrogen-rich environment and is completely burned. The apparatushas the advantages that were already mentioned above.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention will be explained subsequently with the aid of preferredembodiments with reference to the drawings; shown in the drawings:

FIG. 1 a schematic cross-sectional illustration through a burner; and

FIG. 2 a schematic block diagram of a substrate treatment apparatus intowhich is integrated a device for the production of a process gaspursuant to the present invention.

DESCRIPTION OF PREFERRED EMBODIMENTS

FIG. 1 shows a schematic illustration of a burner 1 in which, pursuantto the inventive method, oxygen and hydrogen are burned to form a gasthat contains water vapor.

The burner 1 is provided with a housing 3 that in the interior includesa combustion chamber 5. The combustion chamber 5 has an inlet 7 that isin communication with a first gas inlet line 8. The first gas inlet line8 is in communication with a supply line 10 via which, as will beexplained in greater detail subsequently, hydrogen is introduced intothe burner 1.

In the region of the first gas inlet line 8, a second gas inlet line 12is also provided. The second gas inlet line 12 extends at leastpartially in the first gas inlet line 8, and is embodied as a so-calledlance. By means of the second gas inlet, as will be explained in greaterdetail subsequently, oxygen is introduced into the burner 1. The secondinlet line 12 has an outlet end 14 that is disposed in the region of thefirst inlet line 8, so that a mixing of the gases introduced via the twoinlet lines 8,12 is already effected in the region of the first inletline 8, before the mixture enters into the combustion chamber.

The region of the first inlet line 8, into which the second inlet line12 opens, is surrounded by a heating ring 17 in order to heat theresulting oxygen/hydrogen gas mixture in this region above its ignitiontemperature, and to ignite it. Alternatively, some other device can alsobe provided for the ignition of the mixture.

Furthermore provided in the housing 3 of the burner 1 is a UV detector20, which is directed toward a combustion region of the oxygen/hydrogengas mixture in order to monitor the burning process. Since oxygen andhydrogen burn with a visible flame, the UV detector can monitor thecombustion process at a measurement range of 260 nm. The UV detector iscoupled with an appropriate control device that stops the supply of gasvia the inlet lines 8 and 12 when the detector determines that the flameis extinguished.

The combustion chamber 5 also has an outlet end 21 that communicateswith an outlet conduit 24 which, as will be explained in greater detailsubsequently with reference to FIG. 2, communicates with a rapid heatingunit or in general a process chamber for the thermal treatment ofsemiconductors.

Provided in the outlet conduit 24 is a non-illustrated oxygen andhydrogen sensor, or an appropriate detection device, in order to detectunburned oxygen or unburned hydrogen in the conduit 24.

FIG. 2 shows a schematic block diagram of an apparatus 30 for thetreatment of semiconductor wafers; the burner 1 of FIG. 1 is integratedinto this apparatus.

The apparatus 30 has a process gas production portion 31 and, forexample, a rapid heating unit 32 in which at least one semiconductorwafer is disposed and is thermally treated. The rapid heating unit 32has, for example, a construction such as is known from DE-A-199 05 524,which originates with the same applicant and to this extent is made thesubject matter of the present invention in order to avoid repetition.The outlet conduit 24 of the burner 1 communicates with an inlet of aprocess chamber of the rapid heating unit 32 in order to be able toconvey process gases, which are produced in the burner 1, into the rapidheating unit.

The process gas production portion 31 of the apparatus 30 includes theburner 1, an electronic control unit 34, as well as a plurality of massflow controllers or gas flow control units 36 to 41, which are eachcontrolled by the control unit 34 to provide a controlled gas flowtherethrough.

The mass flow controller 36 has a gas supply line 43 as well as anoutlet line 44. The supply line 43 is in communication with a gassource. The outlet line 44 is in communication with the conduit 24between the burner 1 and the rapid heating unit 32 in order to introducean additional gas into the process gas produced in the burner 1, whichgas is required in the subsequent process.

The mass flow controller 37 has a supply line 46 as well as an outletline 47. The supply line 46 is in communication with a source of aninert gas, such as nitrogen or argon. The outlet line 47 is incommunication with the supply line 10 of the first inlet line 8 of theburner 1, as well as with the second inlet line 12 of the burner 1.

The mass flow controller 38 has a supply line 50 as well as an outletline 51. The supply line 50 is in communication with an oxygen source orwith a source for some other oxygen-containing gas, while the outletline 51 is in communication with the second inlet line 12 of the burner1.

The mass flow controller 39 has an inlet line 54 that is incommunication with a hydrogen source or with a source for some otherhydrogen-containing gas, as well as an outlet line 55, which is incommunication with the supply line 10.

The mass flow controller 40 communicates with an inlet line 58 as wellas with an outlet line 59. The supply line 58 is connected with anoxygen source or with a source for some other oxygen-containing gas,while the outlet line 59 is in communication with the conduit 24 betweenthe burner 1 and the rapid heating unit 32.

The mass flow controller 41 again has a supply line 62 as well as anoutlet line 63. The supply line 62 is in communication with a hydrogensource or with a source for some other hydrogen-containing gas, whilethe outlet line 63 is in communication with the conduit 24 between theburner 1 and the rapid heating unit 32.

As mentioned previously, the mass-flow controllers 36 to 41 arecontrolled by the control unit 34 so that they either convey controlledquantities of gas from their respective supply lines to their respectiveoutlet lines, or they are closed.

The function of the process gas production portion 31, and an inventivemethod for operating the same, will be explained in greater detailsubsequently with reference to FIGS. 1 and 2.

Prior to the production of a process gas, all of the mass flowcontrollers 36 to 41 are initially closed. Subsequently, the mass flowcontroller 37 is actuated in order to introduce an inert gas into theburner 1 via the supply line 10 as well as the second inlet line 12. Inthis way, the supply lines 10, 12, the burner 1, as well as the outletconduit 24 and possibly the process chamber of the rapid heating unit 32are flushed with inert gas to ensure that no oxygen or hydrogen are inthe burner 1, the conduit 24 as well as the rapid heating unit 32.Furthermore, uncontrolled reactions with residual gases, such as air,can be prevented.

After a prescribed rinsing time, the mass flow controller 37 is closed.Hydrogen is now introduced via the mass flow controller 39 and thesupply line 10 into the burner 1, whereby at least the combustionchamber 5 and possibly also partially the conduit 24 and the processchamber of the rapid heating unit 32 are filled with pure hydrogen. Inthis connection, the flow velocity of the hydrogen can be controlled asdesired. After the combustion chamber is completely filled withhydrogen, the heating device 17 is activated and now oxygen isintroduced into the combustion chamber 5 via the mass flow controller 38and the second inlet line 12. The oxygen is introduced, for example,with a time delay of five seconds relative to the hydrogen. When theoxygen starts to exit from the outlet end 14 of the second inlet line12, the oxygen is immediately ignited and is burned together with thehydrogen. In this connection, it is important that at this point in timethe heating device 17 has already reached the required temperature inorder to prevent the formation, in the combustion chamber 5, of a largequantity of oxyhydrogen gas or an explosive mixture of oxygen andhydrogen. For example, the heating device 17 heats the region at theoutlet end 14 of the inlet line 12 to 700° C. During the combustionthere results a flame that extends into the combustion chamber 5 and isdetected by the UV detector.

The control unit 34 sets the flow of the hydrogen and of the oxygen intothe combustion chamber 5 via the mass flow controllers 38 and 39 in sucha way that more hydrogen is present than is necessary for the combustionof the oxygen, so that the oxygen is burned in a hydrogen-richenvironment. Due to the combustion of the oxygen and of the hydrogen,there is produced in the combustion chamber 5 water vapor that, togetherwith the excess hydrogen, is conveyed through the conduit 24 into theprocess chamber of the rapid heating unit 32. The process gas can beproduced with a high flow of up to 30 slm (standard liters per minute),and is conveyed into the process chamber. As mentioned previously, thereis disposed in the conduit 24 an oxygen sensor that detects the presenceof unburned oxygen in the conduit 24. If unburned oxygen is detected inthe conduit 24, the sensor emits a warning signal to the control unit 34since oxygen in the conduit 24 together with the excess hydrogen canform an oxyhydrogen or explosive gas that upon introduction into theprocess chamber of the rapid heating unit 32 can explode and thus damagethe wafer located therein and possibly also the process chamber itself.After the warning signal is received, the control unit 34 sendsappropriate signals to the mass flow controllers 38 and 39 in order toclose them and thus interrupt the production of process gas in theburner 1. Alternatively, or also in addition, inert gas can beintroduced via the mass flow controller 37 into the burner 1 and intothe conduit 24 in order to prevent the formation of oxyhydrogen orexplosive gas in the burner 1 and to again flush the burner.

If no unburned oxygen is detected in the conduit 24, additional hydrogencan be introduced via the mass flow controller 41 and the line 63 intothe process gas that is disposed in the conduit 24 and comprises watervapor and hydrogen, in order to increase the hydrogen content in theprocess gas to a desired value. Furthermore, to the extent that this isdesired, a further gas can be introduced via the mass flow controller 36into the process gas of water vapor and hydrogen. The thereby resultingprocess gas mixture is now introduced into the process chamber of therapid heating unit 32 for the treatment of a semiconductor wafer. Theprocess chamber of a process heating unit 32 is first flushed with theprocess gas before the thermal treatment of the wafer is started. Forexample, the process chamber is flushed with three times its own volume,which requires, for example, 60 seconds. Only then is the thermaltreatment of the wafer disposed in the process chamber started. Duringthe flushing, the wafer is at a low temperature of 20° C. to 560° C. inorder to prevent a self-ignition of the process gas, which in thebeginning can still be in an undefined composition. Furthermore, onewishes to prevent the wafer from already reacting with the not yetfinally defined process gas. The upper temperature of the wafer dependsupon the process and the type of wafer. For example, with metal-coatedwafers the temperature can be less than 250° C., or even less than 100°C., in order to prevent oxidation or reaction processes in possiblyundefined process gases. A hydrogen-rich wet oxidation, for example forthe selective oxidation of gate-stacks with metal gates or metal gatecontacts, can then be carried out in the process chamber.

If for the process in the rapid heating unit 32 it is necessary, afterthe hydrogen-rich process gas comprising water vapor and hydrogen, toprovide an oxygen-rich process gas comprising water vapor and oxygen,the combustion of the oxygen in a hydrogen-rich atmosphere can bechanged to a combustion in a hydrogen-poor atmosphere. For this purpose,the control unit 34 first activates the mass flow controllers 38 and 39in such a way that oxygen and hydrogen in a stoichiometric ratio areintroduced into the combustion chamber 5 of the burner 1. This resultsin a stoichiometric combustion, whereby pure water vapor is produced andno residual products remain. The stoichiometric combustion or burning iscarried out until the excess hydrogen from the previous hydrogen-richcombustion is displaced from the combustion chamber 5 and possibly fromthe process chamber of the rapid heating unit. The quantity of oxygenintroduced via the mass flow controller 38 can now be increased, so thatan oxygen-rich combustion is effected, i.e. there is more oxygen presentthan can be burned with the hydrogen, so that a process gas comprisingwater vapor and oxygen is formed. This mixture of water vapor and oxygencan now be conveyed via the conduit 24 into the rapid heating unit 32.Furthermore, additional oxygen can be introduced via the mass flowcontroller 40 into the conduit 24 in order to increase the oxygen ratioin a desired manner in the process gas comprising water vapor andoxygen. In an analogous manner, it is also possible to change back fromthe production of an oxygen-rich process gas to the production of ahydrogen-rich process gas, whereby again an intermediate phase isprovided whereby a stoichiometric combustion is effected in thecombustion chamber 5.

It is, of course, also possible to start the burner 1 in such a way thatit initially produces an oxygen-rich process gas and possiblysubsequently is changed to the production of a hydrogen-rich processgas.

The process gas production portion 31 of the apparatus 30 is thus in aposition to produce process gas comprising water vapor and selectivelyoxygen or hydrogen. By means of the mass flow controllers 40 and 41, anydesired mixture ratio of water vapor to oxygen or of water vapor tohydrogen can be established in the process gas.

The control unit 34 is designed in such a way that it always locks themass flow controllers 40 and 41 in opposition to one another, since thesimultaneous introduction of hydrogen and oxygen into the conduit 24would lead to the formation of an oxyhydrogen or explosive gas.Furthermore, it is also possible to mechanically couple the mass flowcontrollers 40, 41 in such a way that they are locked in opposition toone another, i.e. that always only one of the two mass flow controllers40, 41 can be opened. The control unit 34 furthermore provides that themass flow controller 40 is always closed if a hydrogen-rich combustionis effected in the burner 1, since also with the introduction of oxygeninto a process gas comprising water vapor and hydrogen an oxyhydrogen orexplosive gas would be produced. In an analogous manner, the mass flowcontroller 41 is controlled in such a way that it is always closed if anoxygen-rich combustion is effected in the burner 1.

To increase the safety, as already previously mentioned an oxygen andhydrogen sensor is provided in the conduit 24 for detecting unburnedoxygen or unburned hydrogen respectively in the conduit. If after ahydrogen-rich combustion in the burner oxygen is detected in the conduit24, this points to an error, and there exists the danger thatoxyhydrogen or explosive gas if formed in the conduit 24 and/or theprocess chamber of the downstream rapid heating unit 32. Therefore, theappropriate sensor sends a warning signal to the control unit 34 thatcan interrupt the process and possibly introduce inert gas into theburner.

This is applicable in an analogous manner if after an oxygen-richcombustion in the burner 1 unburned hydrogen is detected in the conduit24.

The apparatus 30 is now in a position to process a semiconductor waferin the rapid heating unit 32 with a hydrogen-rich and/or oxygen richprocess gas that contains water vapor. It is possible, during a singlethermal treatment cycle, to switch between a hydrogen-rich and anoxygen-rich process gas that contains water vapor. It is, of course,also possible to switch multiple times between these two process gasesduring a thermal treatment cycle. A switching-over can also be effectedwithin a process chamber between successive thermal treatment cycles.

The apparatus was previously described with the aid of a preferredembodiment of the invention, without, however, being limited to thespecific embodiment. For example, the process gas production portion 31can be connected to a plurality of rapid heating units 32 (or in generalprocess chambers for the processing of semiconductor wafers) that aresupplied in parallel with the same or sequentially with the same ordifferent process gas mixtures. For example, one rapid heating unitcould respectively require an oxygen-rich process gas that containswater vapor, whereas in the other rapid heating unit respectively ahydrogen-rich process gas that contains water vapor is required. Theburner 1 could thus be sequentially used for both units without thenecessity for having to shut down the burner between the supply of theone unit and the other unit, and possibly having to rinse the burnerwith inert gas, since one can change as desired between the productionof an oxygen-rich and a hydrogen-rich process gas that contains watervapor. The burner can be operated at overpressure or underpressure,whereby an operation at underpressure is advantageous since gas isconveyed to the outlet by the underpressure in the combustion chamber.Operating in this manner again leads to a uniform burning condition.

The present invention also encompasses embodiments that result from thecombination and/or the interchange of features of the previouslydescribed examples. It should furthermore be noted that instead of asemiconductor or a substrate, any desired object can be processed withthe process gas produced pursuant to the method or apparatus of thepresent invention, whereby the processing is not limited exclusively tothermal, i.e. temperature-time, treatment cycles.

In apparatus in which the object is heated, for example, viaelectro-magnetic radiation, radiated power-time treatment cycles canalso be involved.

The specification incorporates by reference the disclosure of Germanpriority document 101 19 741.1 filed Apr. 23, 2001 and PCT/EP02/04345filed Apr. 19, 2002.

The present invention is, of course, in no way restricted to thespecific disclosure of the specification and drawings, but alsoencompasses any modifications within the scope of the appended claims.

1. A method of treating objects, including the steps of: providing acombustion chamber; producing a first hydrogen-rich process gas of watervapor and hydrogen in said chamber by burning oxygen in anoverstoichiometric, hydrogen-rich environment in said combustionchamber; and conveying said first process gas into an object-treatmentchamber.
 2. A method according to claim 1, which includes the furtherstep of detecting a presence of unburned oxygen downstream of saidcombustion chamber.
 3. A method according to claim 2, which includes thefurther step of interrupting the method if unburned oxygen is detecteddownstream of said combustion chamber.
 4. A method according to claim 2,which includes the further step of introducing an inert gas into saidfirst process gas if unburned oxygen is detected downstream of saidcombustion chamber.
 5. A method according to claim 1, which includes thefurther step of introducing hydrogen into said first process gasdownstream of said combustion chamber.
 6. A method according to claim 1,wherein prior to burning of the oxygen, said combustion chamber isfilled with pure hydrogen, and wherein oxygen is introduced for thefirst time for triggering the burning.
 7. A method according to claim 1,wherein to produce a second, oxygen-rich process gas, a ratio of oxygento hydrogen in said combustion chamber is changed during the burning. 8.A method according to claim 7, wherein during the changing between aproduction of the hydrogen-rich process gas and the oxygen-rich processgas, a stoichiometric burning of oxygen and hydrogen is carried out fora predetermined period of time.
 9. A method according to claim 8, whichduring a production of the oxygen-rich process gas, includes the step ofdetecting a presence of unburned hydrogen downstream of said combustionchamber.
 10. A method according to claim 9, which includes the step ofinterrupting the method if unburned hydrogen is detected downstream ofsaid combustion chamber.
 11. A method according to claim 9, whichincludes the step of introducing an inert gas into the process gas ifunburned hydrogen is detected downstream of said combustion chamber. 12.A method according to claim 7, which includes the step of introducingadditional oxygen downstream of said combustion chamber after aproduction of the oxygen-rich process gas.
 13. A method according toclaim 1, which includes the step of blocking an oxygen supply linedownstream of said combustion chamber if a hydrogen-rich process gas isproduced in said combustion chamber.
 14. A method according to claim 1,which includes the step of blocking a hydrogen supply line downstream ofsaid combustion chamber if an oxygen-rich process gas is produced insaid combustion chamber.
 15. A method according to claim 1, whichincludes the step of introducing a further fluid into said first processgas downstream of said combustion chamber.
 16. A method according toclaim 1, wherein an oxygen-rich process gas is initially produced insaid combustion chamber by burning oxygen in a hydrogen-poorenvironment, and wherein a ratio of oxygen to hydrogen in saidcombustion chamber is changed for burning the oxygen in thehydrogen-rich environment.
 17. A method according to claim 16, whereinduring a change from the burning of oxygen in the hydrogen-poorenvironment to the hydrogen-rich environment, a stoichiometric burningof oxygen and hydrogen is carried out for a predetermined period oftime.
 18. A method according to claim 1, which includes the step offlushing said combustion chamber with an inert gas prior to the burningprocess.
 19. A method according to claim 1, wherein said first processgas is used for a thermal treatment of at least one semiconductor wafer,and wherein within a treatment cycle a change is made between thehydrogen-rich process gas and an oxygen-rich process gas.
 20. A methodaccording to claim 19, wherein a concentration of hydrogen or oxygen insaid process gas is changed during a thermal treatment cycle.
 21. Amethod according to claim 1, wherein said first process gas is used fora thermal treatment of at least one semiconductor wafer, and whereinduring successive thermal treatment cycles, a change is made between thehydrogen-rich and an oxygen-rich process gas.
 22. A method according toclaim 21, wherein a concentration of hydrogen or oxygen in said processgas is changed during a thermal treatment cycle.
 23. An apparatus forthe treatment of objects and for the production of a process gas for thetreatment of the objects, comprising: at least one process chamber forthe thermal treatment of objects; a burner; a combustion chamberprovided in said burner; at least one oxygen supply line, and at leastone hydrogen supply line, into said combustion chamber; an ignition unitfor igniting an oxygen/hydrogen mixture in said combustion chamber; acontrol unit that is controllable in such a way that for a formation ofa process gas comprising water vapor and hydrogen, oxygen is ignited inan overstoichiometric, hydrogen-rich environment and is completelyburned; and an outlet conduit that communicates with said burner,wherein said outlet conduit is connected to at least one of said atleast one process chamber.
 24. An apparatus according to claim 23,wherein at least one of an oxygen sensor and a hydrogen sensor aredisposed in said outlet conduit of said burner.
 25. An apparatusaccording to claim 23, wherein a hydrogen line is connected with saidoutlet conduit of said burner.
 26. An apparatus according to claim 25,wherein an oxygen line communicates with said outlet conduit of saidburner.
 27. An apparatus according to claim 26, wherein means areprovided for locking said oxygen line and said hydrogen line inopposition to one another.
 28. An apparatus according to claim 23,wherein said control unit is controllable in such a way that acombustion in said combustion chamber is changed from a hydrogen-richcombustion to an oxygen-rich combustion.